Phytoplankton functional diversity and spatio-temporal distribution at the meso-scale are studied in the frame of the A*MIDEX CHROME (Continuous High Resolution Observation of the Mediterranean, https://en-chrome.mio.univ-amu.fr/?page_id=42) project thanks to the combined installation of a Ferrybox system (belonging to the INSTM, Tunis) and a cytosense flow cytometer onboard the CTN’s ferry “Le Carthage”. Samples were collected during the cruises between Tunis-Marseille and Tunis-Genova from October 2016 to January 2017. This led to an mount of 80 transects and more than 7000 samples collected. Data analyses resolved the abundances of up to six phytoplankton functional groups based on size and pigment content.